title: Ultrasonicated Enterococcus faecium SF68 enhances neutrophil free radical production and udder innate immunity of drying-off dairy cows.
abstract: Proper dry cow management is critical not only for subsequent milk production and fertility but also for mastitis control. A phenomenon of immunosuppression was commonly observed in transition cows, an example being the high susceptibility of the mammary gland during early the dry period to new infectious agents. Polymorphonuclear neutrophils (PMN) play important defence roles in the mammary gland of newly dried cows. One of the bactericidal mechanisms of PMN is through producing reactive oxygen species (ROS), which can be efficiently quantified by chemiluminescence (CL) assay. In the current study, the potential of intramammary application of a commercial Enterococcus faecium SF68 (SF68) product to enhance the local innate immunity of newly dried mammary glands was evaluated based on the CL assay. The preliminary experiments in vitro indicated virtual dose-responsiveness of ROS generation from three different cell preparations, bovine blood PMN, bovine blood PMN pre-conditioned with cow milk, and the post-diapedesis model somatic cells from cow milk, on their exposure to phorbol 12-myristate 13-acetate (PMA), viable SF68, and ultrasonicated SF68, but not dry-heated SF68. Because ultrasonication treatment was found to profoundly enhance the immunogenicity of SF68 in vitro, in the following animal trial, single infusion of either 5 or 10×107 original cfu of ultrasonicated SF68 was randomly applied to the front quarters and phosphate-bufferedsaline (PBS) applied to the rear quarters of each of the four experimental cows on the first day of milk stasis. The results showed that within the first post-infusion week, ultrasonicated SF68 induced a faster and greater (P<0·05) recruitment of PMN into mammary lumen with no apparent local or systemic inflammatory sign. Meanwhile, ultrasonicated SF68 also induced a greater (P<0·05) ROS production in response to PMA challenge by in situ somatic cells of mammary secretion. Taken together, ultrasonicated SF68 modulated ROS generation of bovine neutrophils, and would be a potential enhancer of udder innate immunity in drying-off dairy cows. More thorough work is warranted.
authors.affiliation: Department of Animal Science, National Chung Hsing University, Taichung 402, Taiwan, Republic of China.
authors.forename: Hsing-Yi
authors.initials: HY
authors.lastname: Peng
authors.forename: Attapol
authors.initials: A
authors.lastname: Tiantong
authors.forename: Shuen-Ei
authors.initials: SE
authors.lastname: Chen
authors.forename: Piya
authors.initials: P
authors.lastname: Piamya
authors.forename: Wen-Bor
authors.initials: WB
authors.lastname: Liu
authors.forename: Huo-Cheng
authors.initials: HC
authors.lastname: Peh
authors.forename: Jai-Wei
authors.initials: JW
authors.lastname: Lee
authors.forename: Ming-Tsao
authors.initials: MT
authors.lastname: Chen
authors.forename: Hajime
authors.initials: H
authors.lastname: Nagahata
authors.forename: Chai-Ju
authors.initials: CJ
authors.lastname: Chang
mesh_terms: D000818:Animals; D002417:Cattle / Q000276:immunology; D002452:Cell Count; D016984:Enterococcus faecium / Q000276:immunology; D005260:Female; D005609:Free Radicals / Q000378:metabolism*; D007113:Immunity, Innate / Q000276:immunology*; D008321:Mammary Glands, Animal / Q000276:immunology*; D008414:Mastitis, Bovine / Q000276:immunology / Q000517:prevention & control; D008892:Milk / Q000166:cytology; D009504:Neutrophils / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D013010:Sonication / Q000662:veterinary
chemical_list: D005609:Free Radicals; D017382:Reactive Oxygen Species